Support for Summary collector

[buffcode]

Currently gauge, counter and history support is available but summary is missing.

I've already developed this collector and currently running it on some production servers.
It currently only has support for Redis, as we don't use APC and I don't have the time to integrate it.

It would be super-duper if parts of it could be merged or extended.
https://github.com/buffcode/prometheus_client_php/commits/summary-collector

If accepted I will create a PR.

[laurenzgamper]

I would love to have summary support, thumbs up!

[DeyV]

buffcode change is great. I'm waiting for merge request and merge 👍

[jackhopner]

bump would be great to have :D

[danvirsen]

I think there might be a better chance at getting a PR accepted in this fork by @NoelDavies.
This project seems to be completely dead.

[NoelDavies]

Yeah I've got an active fork going with php 7 support

[NoelDavies]

Submit a PR to https://github.com/endclothing/prometheus_client_php and I'll get it approved. It's available at https://packagist.org/packages/endclothing/prometheus_client_php